Thomas Midgley, Jr. Biography

Though trained as an engineer, Thomas Midgley, Jr. is best known as an industrial chemist. He was primarily responsible for four important advances in the field of chemistry: discovering effective antiknock additives for gasoline; developing a practical process for the extraction of bromine from seawater; advancing knowledge of the vulcanization of rubber and the composition of both natural and synthetic rubbers; and developing nontoxic and nonflammable gases for use in refrigeration and air-conditioning. As a result of his endeavors, he was awarded all four of the major American medals for achievements in chemistry.

Midgley was born on May 18, 1889, in Beaver Falls, Pennsylvania, the son of Thomas Midgley and Hattie Lena Emerson Midgley. His father was a prolific inventor, especially of improvements in automobile tires; he was also an entrepreneur, whose business ventures usually proved unprofitable. When he was about six years old, Midgley moved with his family to Columbus, Ohio, where he attended elementary school and the early years of high school. In 1905 he went to Betts Academy, a preparatory school in Stamford, Connecticut. Midgley entered Cornell University in 1907 to study mechanical engineering, and he graduated in 1911.

On August 3, 1911, Midgely married Carrie M. Reynolds. They would eventually have two children. He went to work that same year as a draftsman and designer for the National Cash Register Company in Dayton, Ohio. He left after a year to work with his father in a small company the older man had established to manufacture his improved auto tires. This venture failed, and in 1916 Midgley joined the Dayton Engineering Laboratories Company, known as Delco. The company was headed by Charles Franklin Kettering, a noted engineer and inventor who became Midgley's boss, mentor, and friend; their close relationship was to last until the end of Midgley's life.

Kettering soon put him to work investigating the problem of knock in internal-combustion engines , ignoring Midgley's protest that he was an engineer, not a chemist. Midgley was to spend the next five years on this project, becoming in the process a largely self-taught chemist. "Knock" was an audible pinging sound that developed in internal-combustion engines when they were driven near their maximum load capacity. The knock became worse at high engine-compression ratios, and it could destroy an engine if it continued long enough. Since higher compression ratios were essential to improve engine power and fuel efficiency, the problem had to be solved. Midgley soon determined that knock occurred after ignition of the fuel and that it was the result of a sudden increase in pressure and temperature within the engine cylinders. He also determined that it was caused by the fuel rather than by the engine itself. The problem then became one of finding a substance to add to gasoline that would lower the temperature, and hence the pressure, within the cylinder and thus end the knock.

Searching for a gasoline additive, Midgley and his coworkers at first simply tested a large number of chemical compounds in a process of trial and error. Some substances were found which effectively ended the knock, but they all had some serious drawback. Some were expensive to produce and some had a foul exhaust odor. As time passed and the research grew more sophisticated, Midgley and his colleagues discovered that all of the substances that reduced knock contained chemical elements that occupied a certain part of the periodic table. It then became possible to try compounds of other elements in the same area of the table. On December 9, 1921, they tested tetraethyl lead in an engine and found that a minute amount of it completely suppressed knock .

There were some problems even with tetraethyl lead. In the first place, it tended to foul engine valves and spark plugs. It was eventually discovered that adding bromine to the additive would solve this problem, but bromine was a scarce chemical. Midgely solved this by inventing a method for extracting bromine from seawater , where it is present in very small quantities. A more serious problem was the fact that lead compounds are poisonous and are especially dangerous to workers producing them. At the time tests done by the United States Bureau of Mines concluded that tetraethyl lead could be manufactured safely if proper precautions were followed. It was not until the l970s that growing concern about lead pollution led to a ban on lead compounds in gasoline and the substitution of less toxic substances as antiknock additives .

Delco was absorbed by General Motors in 1920, and in 1924 General Motors and Standard Oil of New Jersey jointly formed a new concern, the Ethyl Corporation, whose purpose was to manufacture tetraethyl lead. Midgley became a vice president of the new organization but continued his chemical research for General Motors. In 1926 he became interested in natural and synthetic rubber and persuaded Alfred Sloan, the president of General Motors, to fund a research project on these materials. His research resulted in a series of scientific papers which greatly advanced the knowledge of the exact composition of natural rubber ; he also improved the understanding of the process of vulcanization of rubber , and he was able to outline possible methods for the production of synthetic rubber. In 1928 Sloan ended financial support of this work because it seemed unlikely to produce any practical commercial results, but Midgley continued the work on his own time and with his own money for many years. He considered his rubber research to be the most truly scientific work he had done, precisely because it produced no immediate practical results.

In 1928, Kettering asked Midgley to do research on a new refrigerant suited for home use. The Frigidaire division of General Motors was then in serious financial difficulties, due primarily to the deficiencies of the refrigeration equipment it produced. One of the most basic problems with all the refrigerators then being made was the refrigerants that were being used, such as sulfur dioxide, methyl chloride, ammonia, and butane. All were either toxic or inflammable. Kettering and Midgley agreed that a suitable refrigerant must be stable, noncorrosive, nontoxic, nonflammable; they also wanted a substance which had a boiling point between -0 and -40° centigrade, and they wanted it to be at least relatively cheap.

When Midgley examined his periodic table, he found that all elements of sufficient volatility for this purpose were clustered on the right-hand side. After rejecting all the elements which were either too unstable or too toxic, he was left with carbon, nitrogen, oxygen, hydrogen, fluorine, sulfur, chlorine, and bromine. Midgley and his assistants examined the physical properties of these elements for flammability and toxicity, and they decided that some compound of fluorine would be ideal. After experimentation, they synthesized dichlorodifluoromethane (soon called "freon") . Subsequent testing that the compound was stable and that it met the other criteria. Midgley revealed his discovery in April 1930 at the annual meeting of the American Chemical Society in Atlanta. He breathed in some freon and then exhaled to extinguish a candle flame, thus dramatically demonstrating that the gas was both nontoxic and nonflammable. General Motors and the Du Pont Company joined together in August 1930 to form Kinetic Chemicals Inc. for the production of freon. Midgley became vice president of the new company. Freon soon became the standard refrigerant for home use.

Midgley devoted most of the remainder of his life to research at the laboratories of Ohio State University in Columbus. He had been awarded the Nichols Medal of the American Chemical Society in 1922; he subsequently received the Perkin Medal of the Society of Chemical Industry in 1937, the Priestley Medal of the American Chemical Society in 1941, and the Willard Gibbs Medal of the American Chemical Society in 1942. He was granted honorary degrees by the College of Wooster in 1936 and Ohio State University in 1944. He published fifty-seven scientific papers and was awarded 117 patents in the course of his career. He was president of the American Chemical Society at the time of his death in 1944.

Midgely was stricken with polio in 1940. In the National Academy of Sciences, Biographical Memoirs, Kettering remembers Midgely computing the odds of a man his age catching polio as "substantially equal to the chances of drawing a certain individual card from a stack of playing cards as high as the Empire State building." Although severely crippled, Midgely remained active, making the best he could of his infirmities. He rigged up a system of ropes and pulleys to assist him in rising from bed. On November 2, 1944, he somehow entangled himself in the apparatus and strangled to death at his home in Worthington, Ohio. He was fifty-five.